Note: We can write 17 as since
Using the note above, we can go from
17
- 8 1/2
---------
to
16 2/2
- 8 1/2
---------
Now just subtract the common parts. So and meaning that
16 2/2
- 8 1/2
---------
8 1/2
So this also means that
17
- 8 1/2
---------
8 1/2